Hi!
This entire conversation is a bit disappointing, mainly because I am a supporter of the free software movement, and like to believe that users should have a right to see the source code of software they use. Obviously not everybody feels this way and not everybody is going to support the free software movement, but I can assure you I personally have no plans on contributing to any WMF project that is Apache licensed, but at the very least MediaWiki core is still GPLv2, even if it makes things a bit more difficult.
You seem to be equating access to source code with GPL, which IMHO is a very narrow view of the world. The open source world is much wider than GPL (even though nobody can deny that GPL projects are a substantial part of it), and there are many successful, widely acclaimed and widely used software projects which are open source and not GPL. Of course, the choice where to contribute and on which condition is entirely yours, but I *personally* would view such stance as somewhat counterproductive, if your goal is to contribute to the world's repository of high quality software that can be accessed to everyone.